Another remarkable inhabitant of ants' nests is a minute cricket, of which I found a single example in the midst of a colony of black ants at Mentone in February, 1874. This miniature cricket is scarcely as large as a grain of wheat, the body, excluding the antennæ and other appendages, measuring only two lines in length. It has been described by Dr. Paolo Savi[120] under the name of Gryllus myrmecophilus. He detected it in the nests of several species of ants in Tuscany, where it lived on the best terms with its hosts, playing round their nests in warm, and retiring into them in stormy weather, while allowing the ants to carry it from place to place during their migrations.
[120] Dr. P. Savi, Osservazione sopra la Blatta acervorum di Panzer in Bibliotheco Italiana, tom. xv. p. 217.
Gryllus myrmecophilus has also been observed in nests of the turf ant (Tetramorium cæspitum) near Paris.[121]
[121] Bulletin Soc. Entom. de France (1872), p. li.
At Mentone I have never found more than this one specimen, and the ants among which it was domiciliated were of a species new to me (Camponotus (Formica) lateralis, Oliv.). This colony of ants was composed of many winged males and females, as well as workers, the last-named measuring from two and a half to three lines in length, and black in colour. In other colonies I have found the workers black, with red head and thorax.
Another ant, not enumerated in my list in Ants and Spiders, is Camponotus (Formica) sylvatica, which I detected in March last under stones on Cap Martin, near Mentone. When disturbed, this ant runs along with its abdomen raised vertically in the air, much as the devil's coachhorse (Staphylinus) does. The same curious habit of erecting the abdomen is found in another ant, not uncommon in decaying wood in the South, Crematogaster scutellaris; and probably all three insects adopt this threatening attitude, which is that of the scorpion preparing to strike and sting, in order to intimidate their enemies, though Crematogaster is the only one which really possesses a sting.
Camponotus sylvatica has the same long legs and slender body as Formica cursor, and is of about the same size; the workers, which are of a dark brown colour, measuring about 31/2 lines in length.
Perhaps it may be well, in concluding these remarks on Harvesting Ants, to call attention to the principal questions which still await solution. The first is one which any observer who travels in Central Europe during the summer may help to solve.
1. Do any ants collect and store seed in Switzerland, Germany, North France, England, or indeed in any of the colder parts of the world?
2. What are the habits of Atta structor and A. barbara when living, as they are known to do, in Switzerland, Germany, and Northern France?